Crack Stitching using HeliBars
Stabilising cracked masonry using HeliBars and HeliBond grout
HeliBar bonded into appropriate bed joints or cut slots with HeliBond grout is the solution to the problem of stabilising cracked masonry.
Masonry may move and crack for a variety of reasons. Foundation movement resulting from movement in foundation soils is a common cause. Cracks may also continue to move and develop as a result of on-going siesmic activity (e.g. vibrations resulting from passing vehicular traffic) and cyclical wet and dry, hot and cold environmental conditions.
Helifix crack stitching addresses the problem by reintroducing structural integrity. HeliBars, once installed, distribute structural loads and wall movement out along their length.
FEATURES AND BENEFITS
- Suitable for all types of masonry including listed and historic structures and those with lime mortar.
- Austenitic stainless steel reinforcing bars.
- Fully concealed, non-disruptive repair system.
- HeliBond is injectable and rapidly produces high compressive strength.
- HeliBars and HeliBond grout produce excellent bond strength within the masonry.
- HeliBars create great axial strength with flexibility.
- No additional stresses are introduced.
- Tensile loads are redistributed along the masonry.
- Masonry remains flexible enough to accommodate natural building movement.
- Minimises chances of the crack developing.
- Reduces the likelihood of further cracking nearby.
- Avoids any costly and disruptive taking down and rebuilding.
- Permanent and sympathetic solution.
TECHNICAL SPECIFICATIONS
BONDING AGENT
- HeliBond cementitious grout...Learn more»
Repairing cracks near corners and openings
Where cracks are less than 500mm from an external corner (A) or an opening (B) at least 100mm should be bent around the corner and bonded into the return wall or bent and fixed into the reveal, avoiding any DPC membrane.
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Points to Note
- Multiple cracks may be stitched using single lengths of HeliBar that are long enough to extend 500mm beyond the outer cracks. For example, three cracks, each 250mm apart, may be stitched using 1.5m lengths of HeliBar.
- Multiple HeliBars may be installed into each slot. Typically, one HeliBar for each leaf of brickwork should be installed into each slot. For example, one HeliBar per slot should be installed when stitching a crack in a single 110mm brick leaf. Two HeliBars per slot should be installed when stitching a 230mm solid wall.
- All mortar must be removed, together with any loose debris, to ensure a sound bond.
- Prepare the slot with HeliPrimer WB or thoroughly wet the slot with clean water.
- As standard, slots should be cut to the full mortar joint height, minimum 8mm and ideally 10mm, to accommodate the 6mm diameter HeliBar.
- As standard, slots should be cut to a depth of 25-35mm. Solid wall 35-45mm.
- HeliBond grout is the recommended bonding agent. Resin may used for smaller jobs or where loads are to be rapidly applied.
- Compatible with lime mortars.
INSTALLATION
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Using an appropriate power cutting tool (e.g. brick saw or angle grinder) with vacuum attachment (e.g. TV50 Vacuum and C-Tec Dust Cowl), rake out or cut slots into the horizontal mortar beds, to a minimum of 500mm either side of the crack, to the specified depth (typically 25-35mm) and at the specified vertical spacing (typically not more than four brick courses or 340mm apart).
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Clean out the slots with a brush or blow pump and apply HeliPrimer or flush with water.
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Using a Helifix Pointing Gun, inject a bead of HeliBond to the back of the slot.
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Using a finger trowel, or similar, push the HeliBar into the grout to obtain good coverage.
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Insert a further bead of HeliBond over the exposed HeliBar, finishing 10-15mm from the face, and ‘iron’ into the slot using a finger trowel.
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Repoint the mortar bed and make good.
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Make good the vertical crack with an epoxy-based weatherproof filler, e.g. CrackBond... More»
| HELIBAR SPECIFICATIONS | |||
|---|---|---|---|
| Material | Diameter | Standard Lengths (mm) | Product Code |
| Grade 316 stainless steel | 6mm | 1m (standard) up to 7m | HBR6 |
| Note: | Typically, cracks will be best stitched using 6mm diameter HeliBar (HBR6). At this diameter, HeliBar can be installed into slots cut to a standard mortar joint height (approx. 10mm) without workmanship difficulties and without masonry disturbance. Multiple strands of HBR6 may also be run into individual slots to achieve particualr results. 8mm and 10mm diameters are also available, however, and may be used to suit unusual or particular circumstances. Contact Helifix for technical assistance. | ||
| INDICATIVE HELIFIX CRACK STITCHING SPECIFICATION | ||||||
|---|---|---|---|---|---|---|
| Common cracked Brick/Cavity/Brick wall | ||||||
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| Material | Bonding Agent | HeliBar ø | HeliBar Length | HeliBar Vertical Spacing | HeliBar Code | HeliBond Code |
| HeliBar | HeliBond | 6 mm | 1000 mm | 4 courses (340mm approx.) | HBR6x1000 | HLB |
